Add/Remove Child doesn't work after dragging parent

I’m making draggable windows with tabs in UMG. You can drag out tab == create new window with that tab. Drop window on another window == merge windows.
Everything works fine and dandy until I drag whole window(DD operation with self as visual and payload). It is still interactive, you can drag tabs and drag window itself, but it doesn’t remove or add tabs. At least visually because when you drag window, remove tab and drop this window on another that removed tab won’t be there.

Maybe I shouldn’t use widget as payload and then add it to canvas?

Engine version is 4.11.1

Here’s the video:

Here’s the zipped project:

Hello dx0ne,

I was able to reproduce this issue on our end with the project provided. I have written up a report ( UE-30073) and I have submitted it to the developers for further consideration. I will provide updates with any pertinent information as it becomes available. Thank you for your time and information.

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